CNN's Dr. Sanjay Gupta tells the story of a severely depressed patient, who
underwent an experimental surgery in which doctors drilled two
holes in her skull to implant a pair of battery-powered electrodes in her
brain.

A small electrical charge then stimulates a part of the brain known
as ³Area 25,² which is a junction box for the circuits that control our
moods. The patients who undergo this procedure have not been helped by
anything else. Not psychotherapy; not meds; not even electro-convulsive
shock therapy. But about two-thirds of the experimental subjects using Deep
Brain Stimulation have improved significantly.

Battery Powered Brain is one of three in-depth stories in one riveting hour hosted
by CNN's Randi Kaye and Drew Griffin. CNN Presents premieres an all-new show tonight at 8pm ET, re-airing at 11:00 pm and 2:00 am ET.

The moment 18-year-old Army Private Tim Josephs arrived at Edgewood Arsenal in 1968, he knew there was something different about the place.

“It just did not look like a military base, more like a hospital,” recalled Josephs, a Pittsburgh native. Josephs had volunteered for a two-month assignment at Edgewood, in Maryland, lured by three-day weekends closer to home.

“It was like a plum assignment,” Josephs said. “The idea was they would test new Army field jackets, clothing, weapons and things of that nature, but no mention of drugs or chemicals.”

But from 1955 to 1975, military researchers at Edgewood were using Army volunteers to test chemicals ranging from potentially lethal nerve gases like VX and sarin to incapacitating agents like BZ. The military also tested tear gas, barbiturates, tranquilizers, narcotics and hallucinogens like LSD.

This top secret Cold War research program initially looked for ways to defend against a chemical or biological attack by the Soviet Union, thought to be far ahead of the United States in “psycho-chemical” warfare. But the research expanded into offensive chemical weapons including one that could, according to one Army film obtained by CNN, deliver a “veritable chemical ambush” against an enemy.

Join CNN's Dr. Sanjay Gupta for more from his investigative report on U.S. soldiers used as drug test subjects. CNN Presents premieres Sunday at 8pm ET, re-airing at 11pm and 2am ET.

She will be remembered as one of the greatest voices of her generation. And many of her closest friends say the troubled star was poised to make a comeback. But that comeback was tragically cut short with her untimely death. Whitney Houston’s soaring talent was shadowed by her struggles with addiction and marriage.

In a special investigation, CNN's Don Lemon looks at her rise to fame, her fall from superstardom, and the final hours in her troubled life.

Three in-depth stories in one riveting hour hosted by CNN's Randi Kaye and Dr. Sanjay Gupta.

CNN Presents premieres an all-new show this Saturday at 8pm ET, re-airing at 11:00 pm ET, 2:00 am ET and the same times on Sunday.

On any given Friday at countless American high schools over four million kids are playing tackle football. Those kids are going head to head and helmet to helmet. But this isn't all fun and games. This sport can be as dangerous as it gets.

Just ask the team at JH Rose High School in North Carolina. Three years ago, the worst happened to this championship team. A tragedy they've little explored, until now. There's a price to be paid by these players on the front lines and lessons to be learned from their experience.

CNN's Senior Medical Correspondent Dr. Sanjay Gupta spent the season with the Rose Rampants, a team trying hard to turn tragedy into triumph. But can they win games and stay safe?

You'll meet players, families and doctors who will tell you something you might not want to hear.. but its something that may just save our kids.

The best estimates are that one third of our public schools have air quality that can cause respiratory problems in children. Our kids spend about half of their waking day in school, but there are no air quality standards for classrooms in the United States.

CNN’s Dr. Sanjay Gupta has been investigating schools as part of his series on Toxic America, and his investigation found schools that are literally making children sick.